Yeah, I don't know if I'd say rebuild or not but some fairly significant changes on defense for sure. I would guess:

Starters
Suh
Barron
Joyner

Depth players
Westbrooks
Wilson
Longacre
Hager
Shields
Hill

I'm not certain but I think Brockers returns. Same with Ebukam though based on Okoronkwo and the Draft he might lose his starting spot. And as you point out Talib and Peters will be back but at least one and possibly both will not in 2020. So they are not just replacing CB4 and CB5 but looking for at least one future starter.